In switch-mode power converters (SMPC), current-mode pulse width-modulation (PWM) control and current-limited pulse-frequency-modulation (PFM) control schemes are widely used due to their fast dynamic response. Both control schemes make use of a monitoring of the input current into the power converter to modify the pulse width in PWM or oscillation frequency in PFM for voltage regulation.
Furthermore, regardless of the type of feedback control, DC-DC converters and linear regulators typically sense the input current for overcurrent (overload) protection. Additionally, the sensed current may be used in current-mode control DC-DC converters for loop control.
The present document addresses the technical problem of providing an accurate indication of the input current into an electronic device (such as a power converter or a linear regulator). A current sensing circuit and an associated method are described, which allow for the determination of the input current with a reduced error. In particular, the described circuit and method allow for an accurate measurement of the input current, wherein a dependence of the measurement accuracy on the level of the input current may be reduced and possibly completely removed.